US548246A

US548246A - Fluid-pressure motor

Info

Publication number: US548246A
Authority: US
Publication date: 1895-10-22
Anticipated expiration: 1912-10-22

Description

(No Model.) 2 SheetsSheet 2.

W. A. BOLE. FLUID PRESSURE MOTOR.

No. 548,246. Patented Out. 2 2, 1895.

. hlilll'lf Ill ANDREW B GRAHAM FNUTO UTND WASHINGYDN DC a E F U ITED STATES PATENT OFFICE.

WILLIAM A. BOLE, OF PITTSBURG, PENNSYLVANIA.

FLUID-PRESSURE MOTOR.

SPECIFICATION forming part of Letters Patent No. 548,246, dated October 22, 1895.

' Application filed J'unelS, 18 95. Serial No. 553,194:- (No model.)

To all whom it may concern:

Be' it known that I, WILLIAM A. Born, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered a certain new and useful Improvement in Fluid- Pressure Motors, of which improvement the following is a specification.

My invention relates to improvements in steam or other fluid pressure actuated motors in which a reciprocating piston or plunger having a limited normal movement in a cylinder is subject to the liability, in case of accident or breakage of some of the parts, of causing damage by moving beyond the normal limits of its travel.

The object of my invention is'to provide an improvement in such fluid-pressure motors whereby damage to the cylinder-head or other parts of the structure may be prevented; and to this end my invention consists, generally stated, in new and improved means for resisting and checkingthe movement of the piston when it passes beyond the usual limit of its stroke, so as to prevent the impact of the piston with the cylinder-head and the consequent shock, damage, or breakage which is usually the result of such impact.

My invention is specially adapted for application to the cylinders of steam-hammers in which the piston is directly connected to a vertically-reciprocatin g hammer-block or die. It is not infrequent for the piston-rod of a steam-hammer to be broken or the hammerblock to become detached from the pistonrod, and in such case the piston, being relieved of the weight of the hammer-block, is suddenly moved upward with great force, beyond the usual limit of its stroke, until it comes in contact with the cylinder-head. The result is damage to the cylinder-head, and sometimes the whole machine is wrecked.

The travel of the piston beyond its usual and proper limits may be due to other causes than those mentioned insteam-hammers or other machines, such as improper handling or derangement or breaking of the valve-gear; but, whatever may be the cause, my invention operates to prevent the damage which might be caused by such movement, and the character of my invention is such that its operation is dependent only on an extra travel-of the piston, which acts immediately and directly to bring into action means for resisting and checking the extra movement.

My improvement constitutes an automatic emergency device which may be easily applied to any ordinary cylinder, which is sim- .ple and inexpensive in construction, which is independent of and unconnected with the usual valve-gear or other devices for controlling the operation of the piston, and which operates independently of any action on the part of the person operating the machine. In case the controlling mechanism of the motor is unintentionally so manipulated by the operator as to cause the piston to pass beyond the proper limit of its stroke, my improvement may operate to prevent accident without even the operator being aware that an accident was imminent.

In the accompanying drawings, Figure 1 is a central longitudinal section through a device embodying my invention and through a cylinder-head to which itis applied, a portion only of the cylinder being shown; Fig. 2, a

similar sectionshowing a modification of my improvement.

In the drawings the piston 2 in the main steam-cylinder 1 is shown in about the posi-' tion which it will occupy when at one extremity of its normal stroke. The cylinderhead 3 is provided with a port or passage 4, which when open forms a communication between the interior of the cylinder 1 and a valve-chamber 6. A valve 5 in the chamber 6, which controls and normally closes the passage 4, is provided with an extension or stem 7, on the outer end of which is formed or secured a piston 8, fitted to work in a chamber 9, which is closed by a cap 10. The chamber 9 is in communication with the interior of the cylinder 1 through a passage or passages formed in the piston 8, stem 7, and. .valve 5, and the outer end of the piston 8 is at all times exposed to the same pressure as that acting on the inner face of the valve 5.

In Fig. 2 of the drawings a single straight passage 12 formed through the valve, valvestem, and piston 8, connects the interior of the cylinder 1 with the chamber 9, and in Fig. 1 the passages 11 in the valve, the passages 12 in the stem, and the passages 13 answerthe same purpose.

The piston 8 is so proportioned that the area of its outer end is about the same as the area of the inner face of the valve which is exposed to the pressure in the cylinder 1, and the opposing steam-pressure sacting on these areas thus balance one another. The exterior diameter of the valve 5 is somewhat greater than the diameter of the piston 8, and as the chamber 6 is at all times charged with fluid under pressure an annular area on the back of the valve 5 is exposed to an unbalanced pressure tending to hold the valve to its seat. The piston 8 and valve 5 may be proportioned as shown, or they may be so proportioned that the oppositely-acting fluid pressures may be exactly balanced, or as nearly balanced as may be desired. A spring 14 bears at one end against the piston 8 and at the other end against a bearing 16, which is secured to or abuts against an adjustable stem 17, whereby the tension of the spring may be adjusted.

The valve-chamber 6 communicates through comparatively large and direct passages 15 and 19 with a boiler or other generator or source of pressure and is normally charged with fluid of the same pressure as that in the source of pressure. The pressure in the chamber 6 and in the source of pressure should be as great or greater than the maximum pressure admitted to the cylinder; but in most cases it will be convenient to connect the chamber 6 directly with the boiler from which steam is supplied to operate the piston 2 in the main steam-cylinder 1.

In Fig. 1 of the drawings a check-valve 18 is shown in position to prevent any return flow of fluid from the chamber; but it is so proportioned and the passage controlled by it is of such size that it ofiers little or no obstruction to the passage of fluid into the chamber. The check-valve may or may not be provided with aspring tending to close it; but as it is desirable that it should close quickly on any increase or excess of pressure in the chamber 6 above that in the passages 15 and 19, I prefer to employ a spring 23, which shall insure the quick closing of the valve, but which shall oiier but little resistance to the opening of the valve.

The check-valve may not in all cases be essential, and in Fig. 2 of the drawings no check-valve is shown.

The valve 5 is provided with a stem or extension 20, which projects into the cylinder 1 and is of such length that the piston 2 in its normal travel will not come in contact with the stem; but when the piston 1 passes beyond the usual. limit of its stroke it will come in contact with the stem 20 and lift the valve 5 from its seat. The stem 20 may be adjusted in length to correspond to the stroke of the piston in any cylinder to which it is applied or to any desired variation in the stroke of the piston and to permit any desired amount of clearance between the piston 1 and the stem 20, and in Fig. 1 of the drawings I have shown means whereby such adjustment may be effected. The stem or extension 20 is screw-threaded, and a contact.- piece 21 is adjustably fitted thereon and bears against a jam-nut 22.

If preferred, the stem 20 may be screwed into the valve 5 instead of being formed integral therewith, and the adjustment may be etfected by turning the stem so as to vary the distance between the stem and the piston 2 when the piston is at the normal limit of its stroke.

It will be obvious that the amount of clearance or the distance which the piston may move before opening the valve may be varied to any desired extent and that other means may be employed for adjusting the opening movement of the valve relative to the movement of the piston 2, and my invention therefore is not limited to any particular adjusting means.

If preferred, a stem or projection may be formed on or secured to the piston 2 or to the piston-rod in position to unseat the valve when the piston 2 passes beyond the limit of its stroke, and when such a construction is employed the stem or extension on the valve which projects into the cylinder 1 may be dispensed with.

My improved emergency device is specially adapted to be employed in combination with a double-acting stea m-hammer having a supply and exhaust port or ports opening into the opposite ends of the main cylinder for the admission and exhaust of fluid in the normal operation of the hammer, and an important feature of my invention is the combination of the emergency device with a main cylinder in which the excessive movement of the main' piston before opening the emergency-passage first cuts off all means of escape for the fluid admitted through the emergentry-passage and thereby insures the eflicient operation of the fluid thus admitted.

When the piston 2 in the main cylinder 1 moves far enough to come in contact with the stem 20 on the valve 5, the piston 2 will cover and close the inner" end of the main steampassage 21, through which fluid is admitted to and released from the upper end of the cylinder 1 in the normal operation of the motor, and therefore during the outward movement of the piston 2 any fluid admitted by the opening of the valve 5 will be prevented from escaping through the passage 24c. On the return movement of the piston 2 the passage 24 will be uncovered by the piston 2 and an immediate release of the fluid admitted through the passage 4 may be effected by the movement of the valve 25 (shown in Fig. 3) if that valve is not alreadyin position to open the passage 24: to the exhaustpassage 27.

In the construction shown in Fig. 3 of the drawings I have shown a piston-valve 25 for controlling the admission of live steam from the passage 28 to the

passages

24 and 26 and its exhaust from the opposite ends of the cylinder 1 through the

passages

24, 26, and 27; but my improvement is not dependent on or limited in its application to any particular form of valve for this purpose. If preferred, a slide-valve or any other form of valve may be employed instead of the piston-valve 25.-

In the construction shown in Fig; 1 when the piston moves beyond the usual or safe limit of its stroke the piston 2 will close the passage 24 and come in contact with the stem 20, the valve 5 will be lifted from its seat, and a sudden admission of fluid under high pressure into the cylinder 1 will be effected. The chamber 6 andthe space in thecylinder 1 between the piston 2 and the cylinder-head 3 will he charged with fluid under the same pressure as that in the boiler or source of pressure, and the fluid acting on the piston 2 will resist movement of the piston 2 and tend to prevent contact of the piston with the cyl-.

inder-head 3. In many instances the mere admission of fluid of comparatively high pressure to the outer side of the piston 2will be sufficient to check the piston and prevent it from coming in contact with the cylinderhead. This will be the case when the boiler or generator with which the valve-chamber 6 communicates is charged with fluid under a very high pressure. The construction shown in Fig. 2, in which the check-valve is omitted, may then be employed, and the maximum pressure acting against the piston 2 and tending to prevent its contact with the head 3 of the cylinder will not exceed the pressure in the boiler or other source of pressure with which the chamber 6 is connected.

In the construction shown in Fig. 1 the check valve Will open suddenly. On the opening of the valve 5 the space outside of the piston 2 in the cylinder 1 and chamber 6 will be suddenly charged with fluid of substantially the same pressure as that in the boiler or other source of pressure, and the check-valve will then quickly close. Unless the initial pressure admitted to the cylinder is sufficient to check the movement of the piston the piston 2 will move toward the cylinder-head 3 and compress the fluid in the cylinder and in the

chambers

6 and 9, and the increase of pressure due to this compression will resist and stop the movement of the piston before it comes in contact with the cylinder-head, thereby preventing damage to the cylinder-head or piston and in many instances destruction of the machine.

The volume of the

chambers

6 and 9 and of the normal clearance-space between the piston 2 and the cylinder-head 3 may be so proportioned that any required degree of compression may be eifected for the purpose of obtaining any desired increase in pressure as the piston moves toward the cylinder-head.

My improvement is essentially an emergency device, which is not brought into action in the normal operation of the machine to which it is applied, but which is always in position to be operated in case of emergency, and which is operated directly and quickly by the part or member of the machine whose movement it is intended to control. The fluid under pressure, which is controlled and held in readiness to be applied by means of my improvement, is admitted to the cylinder only in case of emergency, and it may be supplied from a source of pressure other than that which supplies the motor-fluid for operating the piston in the main cylinder.

In the drawings my improvement is shown applied directly to the head of the steam-cylinder and in such position that the operation of the emergency-valve 5 is effected by direct contact 'of the main steam-pist0n, and such a construction ispreferred, because the operationof my improvement is thereby independent of the point at which breakage of the piston-rod may occur; but my invention is not limited to a construction in which the emergency-valve device is formed on or secured t0 the cylinderhead, or to a construction in which the emergency-valve is operated by the direct contact with the piston.

I claim as my invention and desire to secure by Letters Patent- 1. In a fluid pressure motor, the combina tion, with a cylinder, a piston, and a passage,

for the admission or release of fluid to or from the end of the cylinder, which is in position to be closed by an excessive movement of the piston, of means for admitting fluid under pressure to the cylinder to resist the outward movement of the piston when the piston moves beyond the limit of its normal stroke, substantially as set forth.

2. In a fluid pressure motor, the combination, with a cylinder, a piston, and a passage opening into the end of the cylinderin position to be closed by an excessive movement of the piston, of means, operated by an excessive or abnormal movement of the piston, for admitting fluid under pressure to the cylinder to resist and check the outward movement of the piston when the piston moves beyond the limit of its normal stroke, substantially as set forth.

3. In a fluid pressure motor, the combination, with a cylinder, apiston, and a main steam passage opening into the cylinder in position to be closed by an excessive movement of the piston, of a valve device controlling the admission of fluid under pressure to the cylinder, and means whereby the valve device is operated by a greater than normal movement of the piston, substantially as set forth.

at. In a fluid pressure motor, the combination, with a cylinder, a piston, and a passage through which fluid may be admitted to and released from the end of the cylinder in the normal operation of the motor and which is closed by an excessive movement of the piston, of an emergency passage which forms a comm unioation between the end of the cylinder and a source of fluid under pressure, a valve device controlling and normally closing the emergency passage, and means whereby the valve device is directly operated by a greater than normal movement of the piston, for admitting fluid under pressure into the cylinder to resist and check the movement of the piston, substantially as set forth.

5. In a fluid pressure motor, the combination, witha cylinder and a piston, of a passage which forms a communication between the end of the cylinder and a source of fluid under pressure, a valve device controlling and normally closing the passage, means whereby the valve device is operated by a greater than normal movement of the piston, for admitting fluid under pressure into the cylinder to resist and check the movement of the piston, and means for closing communication between the cylinder and the source of pressure whereby the fluid admitted to the cylinder maybe compressed by the movement of the piston, substantially as set forth.

6. In a fluid pressure motor, the combination, with a cylinder, a piston, and a main supply andexhaust passage opening into one end of the cylinder in position to be closed by an excessive movement of the piston, of an emergency passage which forms a communication between the end of the cylinder and a source of fluid under pressure, a valve device controlling and normally closing the passage, and a stem or projection on the valve device which extends into the cylinder in position to avoid contact with the piston when the movement of the piston does not exceed its normal stroke, and which is moved, by contact with the piston, to open the valve when the travel of the piston exceeds its normal stroke, substantially as set forth.

7. In a fluid pressure motor, the combination, with a cylinder and a piston, of a passage forming a communication between the cylinder and a source of fluid under pressure, a valve device controlling and normally closing the passage, a check or non-return valve for preventing the return of fluid to the source of fluid under pressure, and means whereby the valve device may be operated to open the passage to the cylinder by a greater than normal movement only of the piston, substantially as set forth.

8. In a fluid pressure motor, the combination, with a cylinder and a piston, of a passage forming a communication between the cylinder and a chamber which is connected with a source of fluid under pressure, a valve controlling and normally closing the passage, a piston in the chamber which is connected to the valve and exposed on one side to pressure in the cylinder, a spring tending to oppose opening movement of the valve, and means whereby the valve may be opened by a greater than normal movementof the piston, substantially as set forth.

In testimony whereof I have hereunto set my hand.

WILLIAM A. BOLE.

Witnesses.

T. J. HOGAN, F. E. GAITHER.